In documenting keystrokes
used in various computer applications, just about every trick in the book has appeared and failed to catch on.
I recall several Commodore PET and Vic-20 manuals highlighting each letter in a graphic "keycap;" some of these fonts can still be found.
\ 1 \ \ 0 \ \ spacebar \ \ P \ \ R \ \ I \ \ N \ \ T \ \ spacebar \ ...
The difficulties lie in both printed space, and accurately describing different combination key-strokes.
Press and hold the key labeled Ctrl or Control, press the C key, then release them both.
Many people just write "Ctrl-C" to short-hand this notation.
Microsoft Windows tech writers tried to start a new trend in using the plus (+) symbol between the key names for combinations, and the comma (,) symbol for when you can release everything.
There are a number of OS-specific keys which need special characters or symbols on them; the Apple "command," "flower" or "scribble" key, or Microsoft's "flag" key. These pose challenges to the document-writer, without the proper fonts. New keyboards even come with keys that pop up menus, with a symbol on the key that looks like a pointer selecting from a menu.
Some people describe the Unix, Linux or GNU-oriented Emacs editor disparagingly, or lovingly, because of all its complicated and powerful keystroke combinations. GNU Emacs uses a key it calls Meta, which isn't found on many keyboards at all, these days. Users just have to know that Meta means Esc. GNU Emacs describes on its splash screen:
Type C-h for help; C-x u to undo changes. (`C-' means use CTRL key.)
To kill the Emacs job, type C-x C-c.
Type C-h t for a tutorial on using Emacs.
Type C-h i to enter Info, which you can use to read GNU documentation.
GNU Emacs comes with ABSOLUTELY NO WARRANTY; type C-h C-w for full details.
You may give out copies of Emacs; type C-h C-c to see the conditions.
Type C-h C-d for information on getting the latest version.
A term I heard once for finger contortion keystrokes is the "quadruple-buckey keypress." PC users are familiar with the three finger salute and Macs have their own four finger salute alternative.